Thursday, August 2, 2007 - 8:00 AM
S160
Bioactive fatty acids
Ching Hou, U.S. Department of Agriculture, National Center for Agricultural Utilization Research, 1815 N. University Street, Peoria, IL 61604
Oxygenated fatty acids are useful as specialty chemicals, plasticizers, and biomedicals. Microbial enzymes convert fatty acids to mono-, di-, and trihydroxy fatty acid products. Among them, Bacillus megaterium ALA2 converted n-6 and n-3 PUFAs to many new oxygenated fatty acids. Linoleic acid was converted to: trihydroxy-9(S)-octadecenoic acids (THOAs), 12,17;13,17-diepoxy-16-hydroxy-9(Z)-octadecenoic acid, and 12-hydroxy-13,16-epoxy-9(Z)-octadecenoic acid with 12,13,17-THOA as the main product. 12,13,17-THOA has anti-plant pathogenic fungal activity. The linoleic acid bioconversion pathway by strain ALA2 was established. We also screened 12 Mortierella fungal strains from the ARS Culture Collection for the production of bioactive PUFAs such as dihomo-gama-linolenic acid (DGLA) and arachidonic acid (AA). We found that higher dry cell mass and higher yield of AA production are in the following order: Mortierella elongata, M. parvospora, M. zychae, M. humilis and M. multidivaricata. Although the fatty acid composition of AA in M. alpina was the highest among strains screened, its dry cell weight and oil yield were low. The yield for DGLA production is in the following order: M. hygrophila, M. epigama, and M. nantahalensis. We also found that glycerol, a co-product of biodiesel production from soybean oil, can be used as substrate to produce these bioactive fatty acids.